EP1826492A1 - Arrangement for a combustion chamber of a turbine engine - Google Patents

Abstract

The arrangement has an injection system associated with a circular passage hole (62) in a chamber base (16) of a combustion chamber and mounted so that the system slides diametrically with respect to the hole. A deflector has a fitting ring (64) bearing tenons (66) spaced circumferentially and projecting radially. A sleeve (48) is coaxial to the ring and bears other tenons (72) spaced circumferentially and projecting radially. The system is slidably mounted in the sleeve, and a tab is introduced in a notch (60) to prevent a rotation of the system with respect to the sleeve. Independent claims are also included for the following: (1) a sleeve forming part of a combustion chamber arrangement (2) an injection system forming part of a combustion chamber arrangement (3) a deflector forming part of a combustion chamber arrangement.

Description

TECHNICAL AREA

The invention relates to an arrangement for a turbojet combustion chamber, said chamber comprising a chamber bottom pierced with at least one circular through hole, the arrangement comprising an injection system associated with said at least one through hole and slidably mounted diametrically with respect to the circular passage hole of the chamber bottom and a baffle fixedly mounted on a chamber bottom inside the combustion chamber.

The combustion chambers of the jet turbines comprise an inner wall and an outer wall connected at their upstream ends by an annular bottom to define an annular combustion chamber bottom. Regularly distributed injection systems on the periphery of the bottom of the combustion chamber deliver a mixture of air and fuel which is ignited to provide combustion gases.

The fuel is supplied to the injection system by an injector mounted on an outer casing wall and whose head is centered on the injection system. In addition, a deflector protects the chamber bottom of the flames of the combustion chamber. However, there are differential expansions between the combustion chamber and the housing. It is therefore necessary to provide a catch-up of this differential expansion.

In a first type of arrangement (see for example the document EP 1 290 378 ) the injector head is centered on a sliding bushing which can move radially relative to the injection system so as to compensate for the differential expansion of the combustion chamber relative to the housing.

However, there are injector heads that comprise, in addition to a central nozzle, peripheral nozzles that spit in a secondary auger or external twist injection system. In this case it is not permissible to allow a displacement of the injector head relative to the injection system because the injector head must be permanently centered with respect to the injection system. The retrofit of the differential expansions must therefore be done by sliding the injection system relative to the chamber bottom. The invention relates to an arrangement of this type.

On the other hand, according to another requirement, it is necessary that in case of breakage of one of the brazings by which the constituent parts of the arrangement are assembled, no part can be detached and come crashing into the combustion chamber. and the downstream part of the engine, including the HP turbine, which could lead to an explosion of the engine.

The subject of the invention is precisely an arrangement for a turbojet combustion chamber that makes it possible to achieve these objectives. On the one hand this arrangement must allow a sliding of the injection system with respect to the bottom of room. On the other hand, it must be designed in such a way that no part can go downstream in the event of breakage of a solder.

These objects are achieved, in accordance with the invention, by the fact that the deflector comprises an engagement ring carrying radially protruding first spaced circumferentially spaced tenons and that the arrangement comprises a sleeve coaxial with the interlocking ring of the baffle and bearing radially protruding second spaced apart second studs, the first and second studs being spaced apart sufficiently to allow passage of the first studs between the second studs and then, by rotation, engagement of the first studs behind the second tabs; to prohibit a spacing of the deflector and the sleeve in an axial direction, the injection system being slidably mounted in the sleeve, anti-rotating means being provided to prevent rotation of the injection system relative to the sleeve.

Thanks to these characteristics, the retrofit of the differential expansions of the casing relative to the combustion chamber is at the bottom of the chamber and no part can come crashing into the combustion chamber or the turbine in case of rupture of a solder.

In a particular embodiment, the injection system comprises a floating ring slidably mounted in the sheath.

In another particular embodiment, the sleeve has the shape of a cup having a bottom on which the floating ring can slide and a flange, the sliding ring being retained by a closure ring welded to the flange.

Advantageously, the interlocking ring passes through the passage hole of the chamber bottom.

Preferably, the first tenons are directed radially outwards and the second tenons are directed radially inwardly.

Advantageously, the anti-rotating means which prohibit rotation of the injection system with respect to the sheath consist of a tongue of orientation of the floating ring and a notch formed in the rim of the sheath, the orientation tongue being introduced into the notch.

In a preferred embodiment, the arrangement comprises an orientation finger which passes through the chamber bottom and which engages, at one end, in an orientation notch of the deflector and, at another end, in a notch of orientation of the sleeve, the orientation finger imposing a defined angular orientation of the baffle and the sleeve relative to the chamber bottom and, consequently, a specific angular orientation of the sleeve and the deflector relative to each other.

Preferably, the floating ring is provided with a multitude of ventilation holes therethrough.

More preferably, the ventilation holes of the floating ring are arranged in such a way that they are opposite the deflector in an area where there is a clearance between the injection system and the deflector below a limit value and clear of the deflector in an area where the clearance between the injection system and the deflector is greater than this limit value.

On the other hand, the invention relates to a turbojet engine comprising an arrangement according to the invention, as well as a sheath, an injection system and a deflector forming part of the arrangement.

• la figure 1 est une vue générale d'une chambre de combustion comportant un agencement conforme à l'invention ;
• la figure 2 est une vue de détail du système d'injection faisant partie de l'agencement de la figure 1 ;
• la figure 3 est une vue en coupe de la tête d'injecteur montée sur le système d'injection de l'invention ;
• la figure 4 est une vue éclatée montrant le montage du fourreau sur le déflecteur ;
• la figure 5 est une vue de détail d'un doigt d'orientation du fourreau et du déflecteur par rapport au fond de chambre ;
• la figure 6 est une vue éclatée en perspective de l'agencement de l'invention ;
• la figure 7 est une vue assemblée en perspective de l'agencement de l'invention ;
• les figures 8 à 10 sont trois vues de détail qui montrent le fonctionnement des trous de ventilation de la bague flottante.

Other features and advantages of the invention will become apparent on reading the following description of exemplary embodiments given by way of illustration with reference to the appended figures. In these figures:

• Figure 1 is a general view of a combustion chamber comprising an arrangement according to the invention;
• Figure 2 is a detail view of the injection system forming part of the arrangement of Figure 1;
• Figure 3 is a sectional view of the injector head mounted on the injection system of the invention;
• Figure 4 is an exploded view showing the mounting of the sleeve on the baffle;
• Figure 5 is a detail view of an orientation finger of the sleeve and the deflector relative to the chamber bottom;
• Figure 6 is an exploded perspective view of the arrangement of the invention;
• Figure 7 is an assembled perspective view of the arrangement of the invention;
• Figures 8 to 10 are three detail views that show the operation of the ventilation holes of the floating ring.

FIG. 1 shows a partial schematic sectional view of a turbojet combustion chamber designated by the general reference 2 comprising an arrangement according to the present invention. The combustion chamber 2 has a shape of longitudinal symmetry of revolution with respect to a general axis of the turbine (not shown). It comprises an inner casing wall 4 and an outer casing wall 6. An inner chamber wall 8 delimits a passage 10 with the inner casing wall 4 and an outer chamber wall 12 delimits a passage 14 with the outer casing wall 6.

The walls of the inner 8 and outer 12 chambers are joined by a chamber bottom 16 at their upstream ends. A plurality of injection systems 18, for example from 14 to 22, regularly spaced angularly (only one injection system has been shown in FIG. 1) are provided on the chamber bottom 16. For each injection system 18 an injector 20 is mounted on the outer casing wall 6. The injector comprises an injector head 22 centered on the injection system 18 of axis XX.

The operation of the combustion chamber module is as follows. The pressurized air from the compressor enters the chamber of combustion through the passage 26, as shown schematically by the arrow 28. Part of the air passes through the central opening of the fairing 30 while the rest of the air flow directed from the outside of the fairing to the passages 10 and 14 as shown diagrammatically by the arrows 34 and 36. Openings (not shown) are provided in the inner and outer walls 8 and 12 of the combustion chamber to allow the entry of air from the passages 10 and 14.

The air entering the shroud 30 is rotated in the primary swirler 38 of the injector head 22 and in the secondary swirler 40 of the injection system 18. It mixes with the fuel delivered by the injector head 22. The gas mixture enters the combustion chamber in which it is ignited.

FIG. 2 shows a detailed view of the injection system 18. It consists of a bowl 42, the secondary swirler or external swirler 40, already mentioned, and the centering ring 44. The latter is thus designated because it allows the centering of the injector head 22 relative to the injection system 18. The injection system 18 is slidably mounted relative to the chamber bottom 16 by means of a floating ring 46 formed in one piece with the bowl 42 and which slides in a sleeve 48 secured to the chamber bottom 16.

The deflector 50 protects the chamber bottom 16 of the flames of the combustion chamber.

FIG. 3 is an enlarged view of the injector head 22 mounted on the system 18. As previously explained, the injector head 22 has a central nozzle 52 and peripheral injection points 54 which spit in the secondary swirler 40. It is therefore necessary that the injector head 22 is permanently centered perfectly with respect to the injection system 18. This is the reason why it can not be slidably mounted relative to the injection system, as is done in some arrangements. The injector head is thus centered on the centering ring 44 of the injection system 18 and it is the assembly of the injector head and the injection system which is slidably mounted relative to the chamber bottom 16. in the sleeve 48. For this purpose the floating ring 46 integral with the bowl 42 is slidably mounted in the sleeve 48 closed by the closure ring 56. Anti-rotating means are provided to prevent rotation of the injection system relative to the sleeve 48. In the embodiment described these means consist of a tongue 58 which is part of the floating ring 46 and which is inserted into a notch 60 formed in a rim of the sheath.

In this way the injection system can move radially with respect to the baffle 50 and the chamber bottom 16. In FIG. 3, the injection system has been shown in a centered position, however, it is understood that the system of FIG. injection can move between a first eccentric position in which the play at one end, for example the inner end, is zero and a second position eccentric in which the game at the other end is zero.

The deflector 50 is fixedly mounted on the chamber bottom 16 inside the combustion chamber. There is shown in Figure 4 a preferred embodiment of fixing the baffle on the chamber bottom. The chamber bottom 16 has a circular through-hole 62. The deflector 50 has an interlocking ring 64 which engages in the through-hole 62. The interlocking ring comprises studs 66 which are regularly distributed, for example six in the exemplary embodiment shown. The sheath 48 has the shape of a cup having a bottom on which the floating ring can slide and a flange 68 in which is formed a notch 60 for receiving the tongue 58 of the floating ring 46.

The tenons 66 alternate with notches 67. In the example shown, the length of the tenons 66 is equal to that of the notches 67. In other words, given the fact that there are six tenons and six notches in the For example, each tenon and notch extend at an angle at the center of 15 °. Finally, the deflector 50 has an orientation notch 69.

In a manner similar to what has been described for the engagement ring 64, the sleeve 48 comprises six pins 72 regularly distributed angularly alternating with six notches 74 whose length is equal to that of the tenons in the example shown. In other words, as for the interlocking ring 64, each of the tenons 72 and each of the notches 74 extends over a central angle of 15 °. The sleeve 48 comprises furthermore, an orientation notch 76. On the other hand, an orientation notch 78 is formed in the circular through-hole 62 of the chamber bottom 16.

The mounting of the deflector 50 on the chamber bottom 16 is carried out as follows. The insertion ring 64 of the deflector 50 is first introduced into the circular through-hole 62 so that the tenons 66 protrude from the chamber bottom 16. Then, from the position shown in FIG. 4 in which the orientation notches 69 of the baffle 50, 76 of the sleeve 48 and 78 of the chamber bottom 16 are aligned, the sleeve 48 is turned in one direction or the other by a fraction of a turn in such a way that the pins 72 of the sleeve 48 are opposite the notches 67 of the engagement ring 64. In the example described, it is therefore necessary to turn the sleeve 48 by an angle of 15 ° in the direction of clockwise or in the opposite direction to that of the hands of a watch. The sheath is then engaged on the interlocking ring of the deflector, the tenons 72 of the sheath 48 passing between the tenons 66 of the interlocking ring 64. The sheath having been fully engaged, it is rotated by a fraction turn in the opposite direction of the previous direction so that the three orientation notches are aligned again. An orientation finger 78 is then pressed into the three notches 76, 78 and 69 so as to immobilize these three parts in relative position relative to one another. A correct angular orientation being guaranteed by the insertion of the orientation finger 80, the whole assembly is brazed. It is understood that even in the event of breakage of brazing, the baffle 50 will be retained by these lugs 66 engaged lastly with lugs 72 of sheath 48. Thus, even in the case of defective brazing, the deflector can not be sucked into the combustion chamber, according to one of the essential features of the invention.

FIG. 5 shows a detail view which shows the insertion of the orientation finger 80 into the orientation notches respectively of the sleeve 48, the chamber bottom 16 and the deflector 50.

FIG. 6 shows an exploded perspective view of the deflector, the chamber bottom 16 of the sleeve 48 of the injection system 18, the closure ring 56 and the injector 20 with its injection head 22. In Figure 7, these different parts were shown in the assembled position.

The assembly is carried out as follows. The deflector having been fixedly mounted on the chamber bottom (16), and brazed in this position as explained above, the floating ring 46 of the injection system 18 is inserted into the sleeve 48, the orientation tab 58 being introduced into the notch 60 of the sleeve 48. The closure ring is then inserted into the sleeve and welded in this position by three or four circumferentially distributed weld beads. In this way it is easy to replace the injection system if necessary. For this it is sufficient to grind the weld beads, to remove the closure ring and the injection system.

The injection system being retained by the closing ring, it can slide freely in a radial direction within the limit of the clearance between the bowl and the sleeve 48. The head 22 of the injector is then introduced into the centering ring of the system. injection.

Note in Figures 6 and 7 the tongue 58 inserted into the notch 60 of the sleeve 48. There is also the presence of ventilation holes 82 formed in the floating ring 46. As can be seen in Figures 8, 9 and the function of the ventilation holes 82 is to cool the baffle 50. In Fig. 8 the injection system has been shown in nominal position centered with respect to the deflector; FIG. 9 shows an area in which the clearance between the deflector and the injection system (more precisely the bowl) is minimal and in FIG. 10 an eccentric position of the injection system with respect to the deflector 50 in which the game between these two pieces is maximum. In the position of Figures 8 and 9, that is to say in the centered position and minimum play position, the deflector 50 is sufficiently cooled by a flow of air from the ventilation holes 84 which lick it. This is the reason why in FIGS. 8 and 9, the ventilation holes 82 of the floating ring 46 are closed because they are opposite the deflector 50. Therefore, in these positions, no air flow of ventilation circulates through the ventilation holes 82. In contrast, in the position shown in the figure 10, the ventilation holes 82 are disengaged from the deflector 50. Therefore, a stream of air flows through these holes to cool the deflector 50.

Claims (13)

An arrangement for a turbo reactor combustion chamber, said chamber having a chamber bottom (16) pierced with at least one circular through-hole (62), the arrangement comprising an injection system (18) associated with said air hole circular passage (62) and mounted to slide diametrically with respect to the circular passage hole (62) of the chamber base (16) and a deflector (50) fixedly mounted on the chamber floor (16) inside the chamber of characterized in that the baffle (50) has an interlocking ring (64) carrying circumferentially spaced, radially protruding first studs (66) and that the arrangement includes a sleeve (48) coaxial with the interlocking ring (64) of the deflector and bearing radially spaced second spaced apart second pins (72), the first and second tenons (64, 72) being spaced apart sufficiently to allow passage of the first pins therebetween; conds then hold, by a rotation, the engagement of the first tenons behind the second tenons so as to prohibit a separation of the deflector (50) and the sleeve (48) in an axial direction, the injection system (18) being mounted sliding in the sleeve (48) anti-rotating means (58, 60) being provided to prevent rotation of the injection system (18) relative to the sleeve (48). Arrangement according to claim 1, characterized in that the injection system (18) has a floating ring (46) slidably mounted in the sleeve (48). Arrangement according to claim 2, characterized in that the sleeve (48) has the shape of a cup having a bottom on which the floating ring can slide and a flange (68), the floating ring (46) being retained by a ring closure member (56) welded to the flange. Arrangement according to one of claims 1 to 3, characterized in that the interlocking ring (64) passes through the through hole (62) of the chamber floor (16). Arrangement according to one of claims 1 to 4, characterized in that the first pins (66) are directed radially outwardly and in that the second pins (72) are directed radially inwardly. Arrangement according to one of claims 3 to 5, characterized in that the anti-rotating means which prohibit rotation of the injection system (18) relative to the sheath (48) consist of an orientation tongue (58) of the floating ring (46) and a notch (60) formed in the flange (68) of the sleeve (48), the orientation tongue (58) being introduced into the notch (60). Arrangement according to one of claims 1 to 6, characterized in that it comprises an orientation finger (80) which passes through the chamber bottom (16) and which engages at one end in an orientation slot ( 69) of the deflector (16) and at a another end in an orientation notch (76) of the sheath (48), said orientation finger (80) imposing a determined angular orientation of the deflector (50) and the sleeve (48) relative to the chamber bottom (16) and, therefore, a specific angular orientation of the sheath (48) and the deflector (50) relative to each other. An arrangement according to claim 2 or one of claims 3 to 7 when related to claim 2, characterized in that the floating ring (46) is provided with a plurality of ventilation holes (82) therethrough. Arrangement according to claim 8, characterized in that the ventilation holes (82) of the floating ring are arranged in such a way that they are opposite the baffle (50) in an area where there is clearance between the system of injection (18) and the deflector (50) below a limit value and released from the deflector (50) in an area where the clearance between the injection system (18) and the deflector (50) is greater than this limit value. Turbojet engine characterized in that it comprises an arrangement according to one of claims 1 to 9. Sheath forming part of an arrangement according to one of claims 1 to 9. Injection system forming part of an arrangement according to one of claims 1 to 9. Deflector forming part of an arrangement according to one of claims 1 to 9.

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